let ws;
let lastMessageTimestamp = 0;
const IDLE_THRESHOLD_MS = 1000;
const loadingIndicator = document.getElementById("loadingIndicator");

function setLoadingIndicator(visible) {
    if (!loadingIndicator) {
        return;
    }

    loadingIndicator.classList.toggle("hidden", !visible);
}

function updateLoadingState() {
    const isConnected = ws && ws.readyState === WebSocket.OPEN;
    const idle = Date.now() - lastMessageTimestamp >= IDLE_THRESHOLD_MS;

    setLoadingIndicator(isConnected && idle);
}

function connectWS() {
    ws = new WebSocket("ws://" + location.host + "/ws");

    ws.onopen = () => {
        console.log("WebSocket connesso");
        lastMessageTimestamp = Date.now();
        setLoadingIndicator(false);
    };

    ws.onclose = () => {
        console.log("WebSocket disconnesso, retry...");
        setLoadingIndicator(false);
        setTimeout(connectWS, 5000);
    };

    ws.onmessage = (event) => {
        let data;

        try {
            data = JSON.parse(event.data);
        } catch (e) {
            console.error("Invalid JSON received", e);
            return;
        }

        lastMessageTimestamp = Date.now();
        setLoadingIndicator(false);

        // Update Box_A
        if (data.box_a) {
            const boxA = data.box_a;
            document.getElementById("datavalid").textContent = boxA.datavalid ?? "-";
            document.getElementById("timestamp").textContent = boxA.timestamp ?? "-";
            document.getElementById("volts_gen").textContent = boxA.volts_gen ?? "-";
            document.getElementById("eng_rpm").textContent = boxA.eng_rpm ?? "-";
            document.getElementById("adc_read_time").textContent = boxA.adc_read_time ?? "-";
            document.getElementById("n_queue_errors").textContent = boxA.n_queue_errors ?? "-";

            const coils12A = boxA.coils12 || {};
            const coils34A = boxA.coils34 || {};

            document.getElementById("coils12_spark_delay").textContent = coils12A.spark_delay ?? "-";
            document.getElementById("coils34_spark_delay").textContent = coils34A.spark_delay ?? "-";
            document.getElementById("coils12_spark_status").textContent = coils12A.spark_status ?? "-";
            document.getElementById("coils34_spark_status").textContent = coils34A.spark_status ?? "-";
            document.getElementById("coils12_sstart_status").textContent = coils12A.sstart_status ?? "-";
            document.getElementById("coils34_sstart_status").textContent = coils34A.sstart_status ?? "-";
            document.getElementById("coils12_peak_p_in").textContent = coils12A.peak_p_in ?? "-";
            document.getElementById("coils34_peak_p_in").textContent = coils34A.peak_p_in ?? "-";
            document.getElementById("coils12_peak_n_in").textContent = coils12A.peak_n_in ?? "-";
            document.getElementById("coils34_peak_n_in").textContent = coils34A.peak_n_in ?? "-";
            document.getElementById("coils12_peak_p_out").textContent = coils12A.peak_p_out ?? "-";
            document.getElementById("coils34_peak_p_out").textContent = coils34A.peak_p_out ?? "-";
            document.getElementById("coils12_peak_n_out").textContent = coils12A.peak_n_out ?? "-";
            document.getElementById("coils34_peak_n_out").textContent = coils34A.peak_n_out ?? "-";
            document.getElementById("coils12_level_spark").textContent = coils12A.level_spark ?? "-";
            document.getElementById("coils34_level_spark").textContent = coils34A.level_spark ?? "-";
            document.getElementById("coils12_n_events").textContent = coils12A.n_events ?? "-";
            document.getElementById("coils34_n_events").textContent = coils34A.n_events ?? "-";
            document.getElementById("coils12_n_missed_firing").textContent = coils12A.n_missed_firing ?? "-";
            document.getElementById("coils34_n_missed_firing").textContent = coils34A.n_missed_firing ?? "-";
        }

        // Update Box_B
        if (data.box_b) {
            const boxB = data.box_b;
            document.getElementById("b_datavalid").textContent = boxB.datavalid ?? "-";
            document.getElementById("b_timestamp").textContent = boxB.timestamp ?? "-";
            document.getElementById("b_volts_gen").textContent = boxB.volts_gen ?? "-";
            document.getElementById("b_eng_rpm").textContent = boxB.eng_rpm ?? "-";
            document.getElementById("b_adc_read_time").textContent = boxB.adc_read_time ?? "-";
            document.getElementById("b_n_queue_errors").textContent = boxB.n_queue_errors ?? "-";

            const coils12B = boxB.coils12 || {};
            const coils34B = boxB.coils34 || {};

            document.getElementById("b_coils12_spark_delay").textContent = coils12B.spark_delay ?? "-";
            document.getElementById("b_coils34_spark_delay").textContent = coils34B.spark_delay ?? "-";
            document.getElementById("b_coils12_spark_status").textContent = coils12B.spark_status ?? "-";
            document.getElementById("b_coils34_spark_status").textContent = coils34B.spark_status ?? "-";
            document.getElementById("b_coils12_sstart_status").textContent = coils12B.sstart_status ?? "-";
            document.getElementById("b_coils34_sstart_status").textContent = coils34B.sstart_status ?? "-";
            document.getElementById("b_coils12_peak_p_in").textContent = coils12B.peak_p_in ?? "-";
            document.getElementById("b_coils34_peak_p_in").textContent = coils34B.peak_p_in ?? "-";
            document.getElementById("b_coils12_peak_n_in").textContent = coils12B.peak_n_in ?? "-";
            document.getElementById("b_coils34_peak_n_in").textContent = coils34B.peak_n_in ?? "-";
            document.getElementById("b_coils12_peak_p_out").textContent = coils12B.peak_p_out ?? "-";
            document.getElementById("b_coils34_peak_p_out").textContent = coils34B.peak_p_out ?? "-";
            document.getElementById("b_coils12_peak_n_out").textContent = coils12B.peak_n_out ?? "-";
            document.getElementById("b_coils34_peak_n_out").textContent = coils34B.peak_n_out ?? "-";
            document.getElementById("b_coils12_level_spark").textContent = coils12B.level_spark ?? "-";
            document.getElementById("b_coils34_level_spark").textContent = coils34B.level_spark ?? "-";
            document.getElementById("b_coils12_n_events").textContent = coils12B.n_events ?? "-";
            document.getElementById("b_coils34_n_events").textContent = coils34B.n_events ?? "-";
            document.getElementById("b_coils12_n_missed_firing").textContent = coils12B.n_missed_firing ?? "-";
            document.getElementById("b_coils34_n_missed_firing").textContent = coils34B.n_missed_firing ?? "-";
        }
    };
}

function start() {
    fetch("/start");
}

function stop() {
    fetch("/stop");
}

function uploadLittleFS() {
    const fileInput = document.getElementById("littlefsFile");
    const status = document.getElementById("uploadStatus");

    if (!fileInput || fileInput.files.length === 0) {
        if (status) status.textContent = "Select a file first.";
        return;
    }

    const file = fileInput.files[0];
    const formData = new FormData();
    formData.append("file", file, file.name);

    if (status) status.textContent = "Uploading...";

    fetch("/upload", {
        method: "POST",
        body: formData,
    })
        .then((resp) => {
            if (!resp.ok) {
                throw new Error("Upload failed: " + resp.status + " " + resp.statusText);
            }
            return resp.text();
        })
        .then(() => {
            if (status) status.textContent = "Uploaded: " + file.name;
            fileInput.value = "";
        })
        .catch((err) => {
            if (status) status.textContent = err.message;
        });
}

setInterval(updateLoadingState, 200);
connectWS();